docs: def is_text(bytesio):
      """Return whether the first KB of contents seems to be binary.
  
      This is roughly based on libmagic's binary/text detection:
      https://github.com/file/file/blob/df74b09b9027676088c797528edcaae5a9ce9ad0/src/encoding.c#L203-L228
      """
      text_chars = (
          bytearray([7, 8, 9, 10, 11, 12, 13, 27]) +
          bytearray(range(0x20, 0x7F)) +
          bytearray(range(0x80, 0X100))
      )
      return not bool(bytesio.read(1024).translate(None, text_chars))